Manufacture of incandescent electric lamps



. I H. n. MADDEN.

MANUFACTURE OF INCANDESCENT ELECTRIC LAMPS. APPLICATION FILED JUL 11. 1916.

1,349,686, PatentedAllg. 17,1920.

Fig. 9 Fig. l0.

INVENTOR Harry D. Madden. I

ATTORNEY till UNITED STATES PATENT OFFICE.

HARRY D. MADDEN, OF IRVINGTON, NEW JERSEY, ASSIGNOR TO vWESTIN'GIEIOUSIFI LAMP COMPANY, A CORPORATION OF PENNSYLVANIA.

MANUFACTURE OF INCANDESCENT ELECTRIC LAMPS.

To all whom it may concern in the lamp bulb and attached to the cap end of the bulb by means of a fused seal.

The object of my invention is to provide a sealing-in method whereby the mount shall be accurately centered within the bulb at all times during the assembling and sealing operations, whereby the mount may be pressed into its final position with respect to the bulb in a definite and accurate manner, and whereby the fused joint may be annealed without destroying the centered relation between the mount and the bulb.

In the accompanying drawing, Figure l is a side elevational view of a lamp bulb in the form in which it is received from the lass factory. Fig. 2 is a similar view of the bulb after the lower portion has been removed by the cracking off process. Fig. 3 is a similar view of the bulb after a tubu' lating opening has been pierced therein. Fig. 4 is a side elevational view showing a pierced bulb and a filament-carrying mount in alined relation. Fig. 5 is a view similar to Fig. 4, showing the globe and the mount maintained in proper relation by means of a centering rod. Fig. 6 is a similar view showing the mount introduced within the bulb, and also showing one form of supporting structure for the bulb and the mount. Figs. 7 and 8 are similar views showing, respectively, the application of a fusing fire and a cutting-off fire. Fig. 9 is a similar View showing the seal compacted and subjected to an annealing flame, and Fig. 10 is a similar view showing the bulb produced according to the previous steps and providedwith the usual tub'ula ture.

In assembling the parts of incandescent electric lamps, it has heretofore been the Specification of Letters Patent. Patent d A 17 192 Application filed July 11, 1916.

Serial No. 108,629.

practice to place each bulb and its filamentcarrylng mount upon suitable supports, with the mount inclosed within the bulb, and to rotate them in contact with flames directed upon the portion of the bulb adjacent to the flaring stem of the mount. When the bulb and the stem are fused together, it is necessary for the operator to adjust the mount while the glass is still plastic by inserting an adjusting implement into the lower open end of the stem and bringing the filament-supporting arbor as nearly as possible into central position in the bulb. While making this centering adjustment, the operator also performs the operation of pulling down which consists in seizing the depending leading-in wires with tweezers and drawing the mount a fraction of an inch downward for the purpose of compacting and strengthening the seal. According to the usual practice, the sealing-in operation is complete at this point, although it would be highly desirable to apply an annealing flame to the seal. This is found to be impracticable because the slight fusion which is caused by the annealing flame permits the mount to fall to one side, thus requiring a repetition of the centering adjustment and losing the benefit of the annealing treatment. At best, the mounts are only ap proximately centered within the bulbs, since the centering is wholly dependent upon the operators judgment and skill. The degree to which the mounts are pulled down is also variable, and much breakage results from this fact, inasmuch as the amount of pulling down must be accurate within narrow limits in order to produce perfect seals. A further disadvantage of this method is that the operator, in slipping the bulb over the mount, often destroys the mount by striking the filament or its anchors with the bulb.

According to my present invention, I provide sealing-in machines with automatic .means for centering the mounts within the bulbs during the entire sealing-in operation and for also performing the pulling down operation in an automatic and accurate manner. I accomplish these results by inserting a pointed rod or similar member through the opening in the bulb which is ordinarily provided as a preliminary step to the tubulating operation and bringing ,the polnted end of the rod into definite engagement with the filament-supporting-arbor. The rod is rigidly maintained inalinement with the longitudinal axis of the mount and engages the mount throughout the sealing-in operation, thus insuring the proper positioning of the mount within the bulb. After the seal is formed, the rod is forced downward the necessary distance to depress the mount and produce the effect of the pulling down operation, after which the joint between the mount and the bulb is annealed, the rod is withdrawn from the bulb and the lamp is tabulated and finished according to the usual methods.

The figures of the accompanying drawing illustrate the successive steps by whlch a lamp bulb is prepared for use, sealed with a filament-carrying mount accordlngto my present invention and provided with the usual exhausting or gas-changing tubulature. As received from the glass factory,

the bulb presents the appearance of the bulb 1 shown in Fig. 1. The operation of cracking oft gives the bulb the appearance shown in Fig. 3, and the bulb is then provlded with a tubulating opening 2 in the usual manner, after which the bulb is placed in accurate alinement with a filament-carrying mount 3, the two parts being mounted upon suitable rotatable supports 4 and 5, which are rotated in unison, as shown, by way of example, 1n Fig. 6. While the mount and the bulb are in the position shown in Fig. 4, a rod or other similar member 6 is introduced through the tubulating opening 2 and brought into engagement with the lamp mount. I preferably accomplish this engagement by forming a small depression in the upper button 7 of the arbor 8 which forms a portion of the mount 3 and providing the rod with a pointed end 9 adapted to enter this depression. The purpose of the rod 6 is to maintain the bulb and the mount in accurately centered relation throughout the succeeding operations of fusion and annealing and also to compress the seal in the manner described below. Any other specific centering method may be substituted for the depression and pointed rod just described.

After the rod 6 has been brought into engagement with the button 7 of the filamentcarrying mount, the mount is introduced into the bulb either by raising the mount or by lowering the bulb, such movement being in the direction of the axis of the bulb in order to prevent injury to the filament or its anchors. The relation of the parts at this point is shown in Fig. 6. The bulb and the mount are then rotated in the presence of flames projected from burners 10 corresponding to the melting fire usually employed in sealing-in machines. The effect of these flames is to seal the bulb to the lower aces flaring end 11 of the stem 12 which forms a part of the mount. The lower end of the bulb is next detached by means of a second set of flames constituting the cutting-off fire, and the joint presents the appearance shown in Fig. 8, which also shows a set of burners 13, which correspond to the cutting-off fire of ordinary sealing-in machines. During the fusing operations just described, the mount is maintained accurately in its central position within the. bulb by means of the rod 6 and the support 5.

The joint shown in Fig. 8 is relatively weak and must be compacted by moving the mount longitudinally toward the joint which, as stated above, is usually accomplished manually by means of tweezers. According to my present process, I make use of the centering rod 6 to compact the joint, by moving the rod downward a. definite amount, approximately one-eighth of an inch, thus giving the joint the appearance shown at M in Figs. 9 and 10. The support 5 is withdrawn from the stem after the application of the cutting-off fire, as shown in Fig. 8.

The seal between the mount and the bulb is completed by an annealing treatment illustrated in Fig. 9, annealing flames being projected upon the seal from burners 15. During this annealing treatment, the mount is still maintained in its central position in the bulb by means of the rod 6 and, when the joint has cooled, after leaving the annealing fire, the rod (3 is withdrawn from the bulb, and the ordinary tubulation 16 is applied to the bulb in the usual manner. The annealing treatment effectually removes any strains that may be set up in the seal if the glass is either too hot or too cool at the time when the seal is compacted.

My invention does not require the use of any particular apparatus and many forms of machines may be devised for practising it. Such machines may conveniently be made almost entirely automatic and may operate to perform the cracking-oil, piercing and tubulating operations as well as the. sealing-in operation which I have described in detail. It is also to be understood that the several characteristic features of my method may be utilized independently of one another and that, in general, no limitations are to be imposed upon my invention except such as are indicated in the appended claims.

I claim as my invention:

1. The method of assembling incandescent electric lamps that comprisesintroducing a previously axially alined filamentcarrying mount within a globe, rotating the said parts in the presence of a fiame to unite them by a fused joint, moving the mount longitudinally toward its joint with the globe to compact the said joint, annealing the said joint, and positively maintaining the said mount and the said globe in centered relation throughout the fusing, compacting and annealing operations.

2. The method of assembling incandes cent electric lamps that comprises placing a lamp bulb and a filament-carrying mount in longitudinal alinement, automatically moving one of the said members to introduce the said mount into the said bulb while positively maintaining them in an alined relation, producing a fused joint between the said bulb and the said mount, compacting the fused joint, annealing the said joint and maintaining the bulb and the mount in centered relation during the fusing, compact ing and annealing operations.

3. The method of assembling incandescent electric lamps that comprises placing a pierced lamp bulb and a filament-carrying mount in longitudinal alinement, passing a centering member through the said bulb and into engagement with the said mount, introducing the mount into the bulb, producing a fused joint between the bulb and the mount, and maintaining the engagement between the centering member and the mount during the fusing operation.

4. The method of assembling incandescent electric lamps that comprises placing a pierced lamp bulb and a filament-carrying mount in longitudinal alinement, passing a centering member through the said bulb and into engagement with the said mount, in troducing the mount into the bulb, producing a fused joint between the bulb and the mdunt, and moving the said centering member toward the fused joint to compact the 'said joint, the said centering member being utilized to maintain the bulb and the mount in centered relation during the fusing and compacting operations.

5. The method of assembling incandescent electric lamps that comprises placing a pierced lamp bulb and a filament-carrying mount in longitudinal alinement, passing a centering member through the said bulb and into engagement with the said mount, in troducing the mount into the bulb, producing a fused joint between the bulb and the mount, and moving the said centering member toward the fused joint to compact the said joint and annealing the said joint, the said centering member being utilized to maintain the bulb and the mount in centered relation during the fusing and compacting operations.

6. The method of assembling incandescent electric lamps that comprises supporting a filament-carrying mount at opposite ends in axial alinement with a globe, introducing the mount while still held in such alinement into the globe, and producing a fused joint between the mount and globe while still holding the mount in its alinement with the globe.

7. The method of assembling incandescent electric lamps that comprises positioning a filament-carrying mount in axial alinement with a globe, bringing a supporting element and a centering element into an opposed engagement with the mount, moving such elements to bring the mount into centralized position within the globe and then producing a fused joint between the globe and mount.

8. The method of assembling incandescent electric lamps that comprises supporting a filament-carrying mount in axial alinement with a globe, bringing supporting and centering elements into opposed engagement with the mount, moving such elements to bring the mount into centered position within the globe, producing a fused joint between the mount and globe while themount is still held by the supporting and centering elements, withdrawing one of the supporting and centering elements and actuating the other supporting and centering element to move the mount longitudinally with respect to the globe to compact the fused joint formed.

9. The method of assembling incandescent electric lamps that comprises positioning a filament carrying mount in axial alincment with a globe, bringing support ing and centering elements into engagement with opposite ends of the mount, simultaneously moving such elements to bring the mount into centralized position within the globe, producing a fused joint between the globe and mount while the mount is still engaged by such elements, withdrawing one of such elements and moving the other to move the mount relative to the globe to compact the fused joint formed, and annealing such joint while the second element is still in engagement with the mount.

10. The method of assembling and sealing one vitreous element within another which consists in positioning the elements in axial alinement, bringing supporting and centering members into engagement with opposite ends of one element, simultaneously moving the members to move one element into centered relation within the other element, and producing a fused joint between adjacent ends of the elements while the centering and supporting members still hold one element in proper relative position with respect to the other.

In testimony whereof I have hereunto subscribed my name this first day of July,

HARRYD. MADDEN. 

